Continuous Collision Detection alternatives

Andi.Florin
Posts: 5
Joined: Wed Aug 17, 2011 4:06 pm

Continuous Collision Detection alternatives

Post by Andi.Florin »

Hello,

I am new to physics engines and wish to know if there are alternatives to implementing CCD with Bullet besides using "body->setCcdSweptSphereRadius(1.18f)".

I need accurate collision detection and the sphere isn't satisfying enough. I tried looking in the demos provided but could only find low-level implementations on this topic, like "AppContinuousConvexCollisionDemo", from which I didn't understand a lot. I also tried using btContinuousDynamicsWorld instead of discrete, but that didn't work as expected.

The only solution I found(a very bad one) was to set the fixedTimeStep for the stepSimulation to 1/320f, and increase the maxSubsteps to 15, and also increase the thickness of the objects. I cannot afford this as I am programming for mobile devices.

So my question is, is there a better and cleaner solution on implementing CCD in Bullet, which I might have not noticed?

Sorry if my question is noobish and please give me a hint.

Thanks,
Andi
mi076
Posts: 144
Joined: Fri Aug 01, 2008 6:36 am
Location: Bonn, Germany

Re: Continuous Collision Detection alternatives

Post by mi076 »

I need accurate collision detection and the sphere isn't satisfying enough.
the object doesn't have to be a sphere, CCD sphere should be embedded inside convex rigid body... it enables velocity threshold
Andi.Florin
Posts: 5
Joined: Wed Aug 17, 2011 4:06 pm

Re: Continuous Collision Detection alternatives

Post by Andi.Florin »

mi076 wrote:
I need accurate collision detection and the sphere isn't satisfying enough.
the object doesn't have to be a sphere, CCD sphere should be embedded inside convex rigid body... it enables velocity threshold
To give you more details about my problem and tell why this proved not to be a good solution.

The object that I need CCD for is a thin cylinder(with a circle diameter of 2.4 and a height of 0.2). I tried embedding the CCD shpere inside with a radius of 0.09, but the object behaves unnaturally(it enters walls until the wall reaches the CCD sphere, or it enters the floor and twists around it's center axis).

That is why I would like to know if Bullet supports CCD for convex shapes or if there is another way that produces more accurate results.

Thanks for the reply.